JPH02197230A - Rotor of motor - Google Patents

Abstract

PURPOSE: To hold respective laminates integrally by coating a shaft even in the region between the basic part of commutator and a laminate stack and collecting the coating material for the shaft in a recess thereby securing the coating. CONSTITUTION: The method for manufacturing a rotor comprises a step for providing a recess 32 having an end part where the basic part 30 of a commutator faces a laminate stack 23, a step for coating a shaft 20 even in the region between the basic part 30 of a commutator and a laminate stack 23 and a step for collecting the coating material in a recess 32 and securing the coating. An opening or a groove 35 is made in the side wall 33 of the recess 32 in order to release the air when the coating material enters into the recess 32 thus producing a wedge of the coating material. Consequently, an insulation coating for winding an armature winding is formed and respective laminates can be held integrally.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a rotor for an electric motor, particularly a small horsepower PM DC electric motor, and to an electric motor incorporating such a rotor.

PRIOR ART Many small PM DC electric motors are used in automobiles and are exposed to harsh conditions. The fuel pump electric motor is mounted on the engine block and is subjected to very intense gravitational forces, often reaching 100 G's. A force of this magnitude is
causing a relative movement between the laminated armature stack of the motor shaft and the commutator, pulling armature In+9 hard;
Or cut it off.

The armature stack typically has a structural coating such as an epoxy resin paint. This coating can be flowed along the shaft and onto the commutator base. However, coatings formed on the shaft in this manner tend to crack as the shaft flexes, thus shattering or flaking and displacing the commutator relative to the stack. .

SUMMARY OF THE INVENTION A first feature of the invention provides a method of manufacturing a rotor for an electric motor, the method comprising the steps of attaching an armature lamination stack and a commutator base to a shaft of an electric motor. the commutator base portion having a recess facing the laminate stack at an end; coating the stack with a coating material that hardens to form a structural coating, the coating material being the commutator base portion; and the shaft in the area between the laminated stack
lj, m, and pressing the commutator base portion and the stack onto the shaft to ensure a predetermined spacing before the coating material hardens, collecting the coating material on the shaft in the recess and fixing the coating. It includes steps that are structured so that it can be done.

Preferably, an opening or a groove is provided in the side wall of the recess. These allow air to escape as the coating material enters the recess and provide a wedge plug for the coating material. To provide an electric motor comprising a rotor containing an armature lamination stack and a commutator, the commutator base portion having a recess at its end opposite the stack, and having a commutator along the motor shaft. The stack is provided with a structural coating that extends into the recess in the base portion.

Preferably, the structural coating is an epoxy paint or a derivative thereof commonly used to insulate the laminate stack and form the laminates into a cohesive configuration.

Other preferred features and advantages of the invention will become apparent from the following description and the accompanying drawings.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which: FIG.

(Example) FIG. 1 shows a small horsepower PMD C electric motor having a housing, which includes permanent magnets 11,
The end wall 13 includes a deep-drawn tA case 10 that holds a bearing 12. The case 10 is closed with a plastic end cap 14, which includes a bearing 15,
It holds a brush leap 16 that holds a brush 17, and two terminals 18 (one shown) that are in electrical contact with the brush leap 16. The rotor 19 of the electric chess game includes a shaft 20, and a commutator 21 and an armature 22 attached to the shaft 20.

The armature 22 includes a steel laminated stack 23 that is rigidly fixed to the shaft 20 and a winding 24 that is wrapped around the arms of the armature and connected to the commutator 21. There is.

In the assembled electric motor, the shaft 20 is connected to the bearing 1
2.15, the end cap 14 closes the case 10 and the brush 17 presses against the commutator 21.

Such an assembly as described above is well known in the prior art.

In use, the illustrated electric motor is subjected to high accelerations along shaft 20. The laminated stack 23 and the commutator 21 are firmly fixed to the shaft 20, but the shaft 2
Try to move along 0. It has been known for some time to coat laminate stacks with a coating of epoxy resin paint.

This coating forms an insulating coating on which the armature winding 24 is wound and serves to hold each lamination together. According to the invention, this coating is further configured to serve an additional purpose.

Referring to FIG. 3, commutator 21 includes a molded plastic base portion 30. Referring to FIG. The end face 31 of its base part faces the stack 23 and has a recess 32 surrounding the shaft 20. The recess 32 is
It has an outer wall 33 whose inner surface 34 is frustoconically shaped and tapers outwardly toward the stack of laminates, and a plurality of grooves 35 are formed in the wall 33. To assemble the rotor, a stack of laminations 23 and a commutator 21 are attached to the shaft 20.

The commutator and stack are cornered at a distance greater than that required in the completed rotor. The stack 23 is
It is sprayed with an epoxy resin paint 36 and can flow along the shaft towards the end face 31 of the commutator base section 30 (FIG. 3). A portion 37 of the coating flows onto the shaft between the stack 23 and the commutator 21 . While the coating 36 is still liquid, the commutator and stack are pressed together to the required spacing (FIG. 2). Part 37 of the coating on the shaft is therefore in the recess 32
as a result of which a relatively large coating thickness is formed on the shaft 20 between the commutator base portion 30 and the stack 23 (FIG. 2).

Grooves 35 in the walls 33 of the recess allow air to escape from the four parts. In FIG. 2 it can be seen that the commutator base portion is close to the laminated stack.

The recess walls 32 serve to hold the epoxy paint in place when the coating cracks. Also groove 35
can provide epoxy wedge stopper, so
Helps prevent relative rotation of the armature.

After the coating has hardened, the armature is wound in a conventional manner.

The commutator may be completed before being attached to the shaft, or its commutator segments may be added to the commutator base after it is attached to the shaft.

Various modifications may be made to the described embodiments, including all modifications and equivalents that fall within the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a small horsepower PMDC motor embodying the present invention. FIG. 2 is a partially cutaway side view of the rotor in FIG. 1 with the armature windings removed; FIG. 3 is a partially cut away side view of the rotor of FIG. 2 in the assembly stage; I9... Rotor 20... Shaft 21... Commutator 22... Armature 23... Laminated stack 24... Winding 30... Commutator base part 31... End face of commutator base portion 32... Recess in commutator base portion 33... Outer wall of the recess 34... Inner surface of the recess 35... Groove 36. 37. Epoxy resin paint procedural amendment (method) % formula % 1. Indication of the case 1999 Patent Application No. 266098 2. Name of the invention Rotator for electric motor 3. Person making the amendment Applicant related to the case 4. Agent 5, date of amendment order: January 30, 1990; engraving of the drawing originally attached to the application (no change in content)

Claims (10)

[Claims] (1) attaching an armature laminate stack and a commutator base portion to a motor shaft, the commutator base portion having a recess facing the laminate stack at an end, and hardening to form a structural coating; coating the stack with a forming coating material, the coating material also coating the shaft in the region between the commutator base portion and the laminated stack; and pressing the commutator base portion and the stack onto the shaft. A method for manufacturing an electric motor rotor comprising the step of ensuring a predetermined spacing before the coating material hardens, the configuration being such that the coating material on the shaft can be collected in a recess to secure the coating. (2) The method for manufacturing an electric motor rotor according to claim (1), wherein the coating is an epoxy resin material. (3) The method for manufacturing a motor rotor according to claim 1 or 2, wherein the recess wall has an opening or a groove. (4) The method for manufacturing a motor rotor according to claim (3), wherein the recess surrounds the motor shaft. (5) The method of manufacturing a motor rotor according to claim (4), wherein the inner surface of the recess wall is tapered radially inwardly as it moves away from the laminated stack. (6) includes a motor shaft, an armature lamination stack mounted on the shaft, and a commutator, the commutator base having a recess at its end opposite the stack; An electric motor comprising a rotor in which the stack is provided with a structural coating extending along and into a recess in a commutator base portion. (7) The electric motor according to claim (6), wherein the coating substantially fills the recess. (8) The electric motor according to claim (6) or (7), wherein the recess wall has a groove. (9) The electric motor according to claim (8), wherein the recess has an outer wall surrounding the electric motor shaft. 10. The electric motor of claim 9, wherein the inner surface of the outer wall tapers radially inwardly away from the stack of laminations.